Some UGT1A1 SNPs have been associated with hyperbilirubinemic diseases such as Crigler-Najjar syndrome types I and II (CNI, MIM #218800 and CNII, MIM #606785), Gilbert syndrome (GS, MIM #143500), as well as severe side effects of medicines, such as diarrhea and neutropenia of the colorectal cancer drug irinotecan [15], [24], [25], [26]. This evidence concerns the gene UGT1A1 and Gilbert syndrome.